1. Field of the Invention
This invention relates to a linear motion ball bearing, and, more particularly, to a linear motion ball bearing having a flange to be fixed to a machine or an apparatus.
2. Description of the Prior Art
A linear motion ball bearing is so formed that several rows of balls receive a load as they make endless circulating movements from and then back to the side of the load through the return circuits in a ball retainer. When the linear motion ball bearing is used in combination with a shaft, light, linear reciprocating movements are obtained due to a minimal frictional resistance based on the close and smooth rolling contact, and this significantly contributes to the saving of energy. A combination of the linear motion ball bearing and a shaft is used extensively for various types of measuring instruments, medical equipment and computer terminal equipment, not to speak of industrial robots.
Especially, in order to set a shaft in a machine or an apparatus conveniently by using such a linear motion ball bearing, a flange-carrying linear motion ball bearing shown in FIGS. 9 and 10 is used. Referring to FIGS. 9 and 10, a ball bearing portion includes a linear motion ball bearing outer sleeve 2 (hereinafter referred to as an outer sleeve) a ball retainer (not shown) fitted in the outer sleeve 2, and balls 3 retained in the ball retainer, with a flange portion 4 being attached to one end of the outer sleeve 2 in the ball bearing portion 1 and provided with bolt holes 5 for use in fixing the flange portion to a machine or an apparatus, and with a shaft 6 supported in the ball bearing portion 1.
When such a flange-carrying linear motion ball bearing is used to move a machine or an apparatus along a shaft both ends of which are fixed, the ball bearing portion 1 is fixed to a portion of the machine or apparatus via the flange portion 4 to enable the machine or apparatus to be moved along the shaft.
The above-described linear motion ball bearing consisting of a ball bearing portion 1 and a flange portion 4 can be fixed to a machine or an apparatus simply and speedily as compared with a linear motion ball bearing not provided with a flange portion but it is not always easy to secure the squareness of the surface of the flange portion 4 at which the flange portion 4 is attached to a machine or an apparatus with respect to the axis of the ball bearing portion 1 when fixing the flange portion 4 to a machine or an apparatus. For example, when the surface of a machine or an apparatus to which the flange portion 4 is to be fixed is black, i.e., not machined, it is necessary that this surface be subjected to scaling and surface finishing. When the scaling is not done, a shim is inserted between the surface of the machine or apparatus to which the flange portion 4 is to be fixed and the flange portion 4, whereby the squareness of the mentioned surface with respect to the axis of the ball bearing portion 1 is secured.
Especially, when such a ball bearing portion 1 is fixed via the flange portion 4 to a machine or an apparatus which is to be mounted on a shaft in an inclined state with respect thereto as will be described later, the mounting requires considerable time and labor and a high bearing fixing accuracy cannot be obtained.
Such an operation increases the number of work hours, and includes a trial and error operation. Therefore, it has been demanded that this operation be improved for obtaining higher bearing fixing accuracy and efficiency.